There has been generally known a cooling system configured to circulate air or liquid refrigerant. For example, the cooling system using the liquid refrigerant is configured to circulate the liquid refrigerant by a pump, cool a heat-generating element by a cooler, and release heat by a radiator. Further, there is disclosed a cooling system in which the liquid refrigerant is boiled by the cooler to enhance cooling performance (see, for example, Patent Literature 1).